This invention relates generally to rotary machines and, more particularly, to a method and a system for reducing internal exhaust turbulence from rotary machines.
Steam and gas turbines are used, among other purposes, to power electric generators. A steam turbine has a steam path which typically includes, in serial-flow relationship, a steam inlet, a turbine, and a steam outlet. A gas turbine has a gas path which typically includes, in serial-flow relationship, an air intake (or inlet), a compressor, a combustor, a turbine, and a gas outlet (or exhaust nozzle). Some known steam turbines are coupled to a condenser. Under normal operating conditions, an engine casing channels exhaust flow axially through the engine to an exhaust diffuser and then the condenser condenses the exhaust. Know casings include cut away ducts which include relief diaphragms. Under abnormal operating conditions, the condenser can fail and cause a rapid pressure increase in the exhaust diffuser. Under this condition, the relief diaphragm is designed to rupture and release steam outside and facilitate preventing damage to the turbine.
An operating efficiency of the turbine depends at least in part on flow dynamics within the turbine, and as such, engine efficiency may be limited by the geometry of aerodynamic components. More specifically, changing the geometric shape of certain aerodynamic components, such as exhaust diffusers, may facilitate reducing flow variations and increasing engine efficiency. However, because relief diaphragms are adjacent the exhaust flow, the cut away ducts may induce turbulence into the exhaust flow path. Such turbulence may cause flow losses which may decrease turbine efficiency.